husky big end bearing

[herne]

So, got to the stage where I'm examining the crank etc. How (or can you) replace the big end bearing on the crank?

 

Cheers

 

G

[spudulike]

So, got to the stage where I'm examining the crank etc. How (or can you) replace the big end bearing on the crank?

 

Cheers

 

G

 

I won't say you can't because anything that is manufactured can be dissmantled but it is well outside of what the vast majority of engineers can or would do including myself.

 

If the big end is shot, replace the crank with either new or a good second user part. If it looks OK with no "up and down" play - "Side to side" is normal, then re-use it and fit new seals plus vac and pressure check the re-assembled engine.

[Stubby]

So, got to the stage where I'm examining the crank etc. How (or can you) replace the big end bearing on the crank?

 

Cheers

 

G

Did you mean the crank bearings ( left and right ) or did you mean the big end bearing in the con rod ?

[spudulike]

Did you mean the crank bearings ( left and right ) or did you mean the big end bearing in the con rod ?

 

Good point Andy - am guessing though, that if the guy knows the correct term for the big end, he probably means the big end.

[Stubby]

Good point Andy - am guessing though, that if the guy knows the correct term for the big end, he probably means the big end.

 

Excelent point , well made Steve ! I shall withdraw into my shell !

[herne]

Yep, big end it is. Crank bearings already out and I can just read the serial numbers on them. Any ideas where to order genuine bearings from?

 

Also when replacing the crank seals would you use something like hylomar on the metal to metal fit (i.e. outside of the seal to internal face of crankcase to ensure a seal?)

 

In addition I intend porting this saw and maybe leaving out the bottom gasket in order to get a touch of squish (sounds like some orrible std)

 

I guess I need to alter the size of the exhaust port at the top? to compensate by the same thickness as the gasket?

 

Never ported anything before so a whole new experience.

 

I intend to 'shotgun' the exhaust a la spud.... so it should be fruity when it's done

[spudulike]

There should be no need to put any sealent around the seal as long as you haven't marked or bruised the casing on removing the old ones. If you have, a smear of hylomar or stud lock will reseal it.

 

Husky parts - Arb Ireland on ebay or Greenstripe - just google them.

 

What saw are we dealing with, on some you can't drop the base gasket out without the piston hitting the top of the cylinder. There should be no need to raise the port when dropping out the base gasket but I personally do to keep the exact port timing.

[herne]

Husky 272 xp is what we're dealing with. I've read round and it seems like you get (typically) .020-.025 squish by dropping the gasket?

 

Final bits of stripping out tonight and found that when the piston ring collapsed it left dents in the top of the pot and a chip about 2.5mm long vertically down from the lower line of the inlet port. This piece of ring also scored right through the piston skirt for about 30mm and bounced up and down on top of the piston leaving pretty patterns... Piston obviously toast and a meteor will be ordered but have people rescued pots with this type of damage? I guess that at least some of the chip will be taken out once I radius the edges of the inlet port but probably not all. The rest of the pot looks ok i.e. no other visible/feelable scores.

 

Thoughts?

 

Regards

 

G

[spudulike]

Husky 272 xp is what we're dealing with. I've read round and it seems like you get (typically) .020-.025 squish by dropping the gasket?

 

Final bits of stripping out tonight and found that when the piston ring collapsed it left dents in the top of the pot and a chip about 2.5mm long vertically down from the lower line of the inlet port. This piece of ring also scored right through the piston skirt for about 30mm and bounced up and down on top of the piston leaving pretty patterns... Piston obviously toast and a meteor will be ordered but have people rescued pots with this type of damage? I guess that at least some of the chip will be taken out once I radius the edges of the inlet port but probably not all. The rest of the pot looks ok i.e. no other visible/feelable scores.

 

Thoughts?

 

Regards

 

G

 

The Squish sounds OK but worth checking once assembled, the pot is difficult to know without an image. Scores and damage to the bore above the exhaust port will be bad news.

 

If you drop the gasket, make sure you clean out any carbon in the combustion chamber directly above t eoutside edge of the piston and also work on the bore area above where the rings have been rubbing on the cylinder as the piston will now travel 0.5mm further in to the bore than before.

[Shane]

Yep, big end it is. Crank bearings already out and I can just read the serial numbers on them. Any ideas where to order genuine bearings from?

 

Also when replacing the crank seals would you use something like hylomar on the metal to metal fit (i.e. outside of the seal to internal face of crankcase to ensure a seal?)

 

In addition I intend porting this saw and maybe leaving out the bottom gasket in order to get a touch of squish (sounds like some orrible std)

 

I guess I need to alter the size of the exhaust port at the top? to compensate by the same thickness as the gasket?

 

Never ported anything before so a whole new experience.

 

I intend to 'shotgun' the exhaust a la spud.... so it should be fruity when it's done

 

I have a brand new crank/conrod unit for a 272 - still in box

with all bearings (small end and both crank ends).

Ref stamped on crank is5017770-01 sweden-e 93 42